Carcinoembryonic antigen is a glycoprotein which is found in various neoplasms and certain fetal tissues. We have found this substance in human sweat by radioimmunoassay and in eccrine and apocrine gland by an unlabeled antibody peroxidase-antiperoxidase method for demonstrating carcinoembryonic antigen in tissue. We will examine the physiology of carcinoembryonic antigen in human sweat, compare its release to sweat rate and sweat electrolyte content, and examine samples of sweat for regional variation in sweat carcinoembryonic antigen activity. Determination of carcinoembryonic antigen activity will be by radioimmunoassay using either goat or rabbit antisera to human carcinoembryonic antigen. Precipitation of carcinoembryonic antigen by aluminum chloride in the acrosyringium may be a mechanism of pharmacologic anhidrosis; this possibility will be studied by immunohistochemical and biochemical methods. Carcinoembryonic antigen can be found in sweat gland neoplasms with immunoperoxidase staining methods but not in other adnexal neoplasms. Preliminary results indicates that the presence of carcinoembryonic antigen within an epithelial neoplasm in skin may be the earliest sign of ductal differentiation. Larger numbers of adnexal tumors will be surveyed. Poorly differentiated adnexal neoplasms may be classified into the sweat gland group if carcinoembryonic antigen can be detected in the tumor mass. Using biochemical techniques, carcinoembryonic antigen will be purified from human sweat by gel filtration and affinity chromatography on concanavalin A-sepharose 4B. Purified carcinoembryonic antigen will be radioiodinated and characterized by charge, molecular weight, antigenic structure, amino acid content, and carbohydrate content. Sweat carcinoembryonic antigen will be compared to carcinoembryonic antigen molecules purified from other sources. This work will shed light on the function of glycoproteins, specifically carcinoembryonic antigen, in the process of sweat formation.